Aromatic imido-esters production



Patented Apr. 3, 195i UNITED STATE S PATENT OFFi-JC AROMATIC IlWIDO-ESTERS PRODUCTION Stanley P. Rowland, Philadelphia, Pa., assignorto Rohm & Haas Company, Philadelphia, Pa.,

7 a corporation ofDelaware No Drawing. Application November 29, 1949,

. Serial No. 130,067

This invention relates to a new processv for the preparation of aromatic imido-esters which have the general formula in .which X represents. an atom or oxygen or sulfur; Z 7 represents a phenylen'e group, CcH4, or a naphthylene group, CH6; the characters R R R and R represent hydrogen atoms or monovalent, organic radicals which are unreactive with acid anhydrides and which therefor are free of hydroxyl groups or amino- 6 Claims. (01. 260- 326) zoline, are reacted may make for a clearer underhydrogen atoms and which preferably are hydro T carbon groups; and in which R also represents the same kind. of mbnovalent, organic radical as R. 2:? 5 butdoes not represent a hydrogen atom.

The process involves a new chemical reaction which comprises chemically combining (a) .phthalic anhydride or a naphthalic anhydride with (b) an oxazoline or'a thiazoline having the formula 'f in in which the Rs and X have the significance described above. This reaction takes place accord ing to the following equation:

o R R3 R4 R6 O+N Z l Iii s A specific example in which phthalic anhydride and a particular oxazoline', -2-h'ptade'cehyl bxastanding, at the outset, of the new reaction.

0 i CHr-CHz ll NOHzCH2OC-CuHaa B-Phthalimidoethyl oleate Careful study. has shown that naphthalic anhydrides-described herein react in the same manner as phthalic 'anhydride and that the oxazolines andthiazolin'es described herein react in the same manner as the oxazoline above. groups represented by Z, X and the five Rs in the general formula given above remain intact and" unchanged during the process, and the reaction does in fact take the course shown above. The organic radicals which'are-represented by Rs must be unreactive with acid anhydrides.

That is, they :must 'be entirely free of such substituentsas hydroxyl groups and amino hydrogen atoms whichv are capable of reacting with acid anhydrides, so that no interfering side-reactions cantake place. It is preferred that these radicals be hydrocarbon radicals such as alkyl, aryl, alkaryl, aralkyl and cycloalkyl groups. The following list includes examples of such suitable,

That is, the

In fact a particularly valuablehydrocarbon radicals, it is a fact that imido-esters are readily prepared from the anhydrides and azolines whose substituents, Rs 1 also contain other elements in addition to carbon and hydrogen. Such substituents however must be inert in the sense that they do not undergo reaction themselves with acid anhydrides. Thus, halogen roups may be present on the R-substituents as well as nitro, ether, keto, aldehydo, sulfonic, carboxyl, or tertiary amino groups.

The process of this invention gives rise to a large number of compounds, many of which were unknown heretofore. All of the compounds, however, fall within the class .described by the above general formula. A large class of operable ox.- azolines and thiazolines are known and are shown in the literature. All of these react with phthalic and naphthalic anhydrides to form phthalimido and naphthalimido esters by the methods set forth in the examples below. All that is required is to substitute an equivalent amount of one azoline; i. e. an oxazoline or a thiazoline, for the particular azolines shown in the examples. Thus in the same manner, the following azolines, of which the skeletal structure is and in which X is an oxygen atom in oxazolines or a sulfur atom in thiazolines, combine in equimolecular amounts with phthalic and naphthalic anhydrides to-form the corresponding phthalimido and naphthalimido esters: 2-phenyl azolines; 2-p-to1yl azolines; 2-o-tolyl azolines; 2- benzyl azolines; 2,-(o-, m-, andp-nitrophenyl) azolines; p-chlorobenzyl azolines; 2-undecyl-5- chloromethyl azolines; 2,4-diphenyl azolines; 2,5- diphenyl azolines; 2-phenyl-5-chloromethyl azolines; 2- (p-nitrophenyl) 5 chloromethyl azolines; 2-(p-nitrophenyl) 5- diethylaminomethyl azolines; 2 (p-nitrophenyl) 5 dibutylaminomethyl azolines; 2:-phenyl- 5,5.-dimethyl azolines; 2-phenyl-5-phenyl-5-methyl azolines; Z-(mand p-nitrophenyl)-5,5-dimethyl azolines; Z-(aor ,B-naphthyl) azolines; 2-p-methoxyphenyl azolines; Z-p-ethoxyphenyl azolines; Z-p-butoxyphenyl azolines; 2-(m-nitro-p-methoxyphenyl) azolines; Z-(p-nitrophenyl) -4-butyl azolines; 2- (p-nitrophenyl-4-pheny1 azolines; 2-phenyl-5- methyl azolines; 2-phenyl-5-ethyl azolines; 2- benzyl-5-methyl azolines; z-styryl-5-methyl azolines; 2-(oand p-tolyl)-5-methyl'azolines; 2- (a and e-naphthyl) -5-methyl azolines; 2-phenyl- 4,5-dimethyl azolines; Z-(p-nitrophenyl)-4,5-dimethyl azolines; 2-phenyl-4-methyl-5-ethyl azolines; 2,4,5-trimethyl azolines; 2-undecyl-4,4-dimethyl azolines; 2-phenyl-4-methyl-4-ethyl azolines; 2-phenyl-4,4-dimethyl azolines; Z-heptadecyl azolines; 2-heptadecenyl azolines; 2-heptadecyl-4,4-dimethyl azolines; 2-heptadecenyl-5- ethyl azolines; 2-phenyl-4-methyl-5-phenyl azolines; 2-methyl-4,5,5-triphenyl azolines; 2- phenyl-4-methyl-5,S-dibenzyl azolines;" Z-heptadecyl-5-diethylaminomethyl azolines; 2-heptadecyl-S-ethyl azolines; 2-heptadecenyl-4,5,5-trimethyl azolines; 2,4,5-tri-isobutyl azolines; 2- heptadecyl 4,4,5,5 tetramethyl azolines; 2- methyl--isoamyll-methyl azolines; Z-heptadecyl-4-propyl-5-methyl azolines; 2,-heptadecenyl-4,4-dimethyl-5-isopropyl azolines; 2-decyl- 4,4-dibutyl-5-methy1 azolines; and Z-heptadecyl- 5-methyl-5-ethyl azolines.

The naphthalic anhydrides which are known to react according to the process of this invention include 1,8-naphthalic, 1,2-naphthalic, and 2,3- napthalic anhydrides. Preference is given to the 1,8-naphthalic anhydride due to its availability. Furthermore, the anhydrides can be substituted by halogen and nitro groups without losing their reactivity with the azolines.

The reactions between the phthalic and naphthalic anhydrides and the azolines takes place fairly readily and often exothermically. Reaction takes place even at room temperature (20 C.) but the rate of reaction is unnecessarily slow. Heating of the reactants accelerates the rate of reaction and for this reason a minimum temperature of C. is recommended. Temperatures up to 300 C. are operable but at the higher temperatures lay-products are frequently formed, including polymeric materials when the group represented by R is unsaturated. Accordingly, an upper temperature of 250 C. is much preferred. For convenience, inert solvents can be employed. Likewise catalysts, such as alcoholates, zinc chloride and the like, can be used, although ordinarily the reaction takes place rapidly enough in the absence of catalysts. Other expedients well known to those skilled in the art, such as variations in pressure, solvent-extraction of the product, excess of one reactant, particularly the azoline, and the like, can be used Without departing from the spirit of this invention which is to prepare phthalimido and naphthalimido esters by reacting, preferably under the influence of heat, equimolar amounts of a phthalic or a naphthalic anhydride and an oxazoline or a thiazoline.

The following examples serve to illustrate the process of this invention:

EXAMPLE 1 Phthalimiodethyl acetate A solution of 22.2 grams of phthalic anhydride,

, 12.75 grams of Z-methyl oxazoline in 35 grams of dioxane was heated in an autoclave at C. for 2.3 hours after which the mixture was poured into water at room temperature. The solid which precipitated was removed by filtration, dried and crystallized from dry ethanol. After recrystallization from dry ethanol the product had a melting point of 88.5" C. A mixed melting point with a known sample of phthalimidoethyl acetate prepared by the acetylation of hydroxyethyl phthalimide showed no depression.

EXAMPLE 2 Phthalz'mz'doethyl 2-ethylhemoate EXAMPLE 3 Phthalimidoethyl oleate In the same equipment as was described in Example 2, a mixture of 1 mole of phthalic anhydride and 1.1 moles of Z-heptadecenyl oxazoline (prepared from oleic acid and ethanol amine) was heated for 4 hours at 200 C. The

fluid product was fractiona'lly-distilled under Vacuum and a fraction wasisolated which boiled at 234-244 C. and 1 mm. of pressure. The analysis showed this compound to contain 3.14% nitrogen as against a calculated nitrogen-content oi 3.07% forphthalimidoethyl oleate.

, EXAMPLE4 Pitthalintidoisopropgjl'linoledta A mixture of 1 mole of phthalic anhydride and 1.1 moles of 2-heptadecadienyl-4-methyl oxazoline (prepared from aminoisopropanol and linoleic acid) was heated in an atmosphere of carbon dioxide for 4 hours at 200. C. in a balloon flask equipped with reflux condenser, thermom-' eter; stirrer and gas-inlet tube. The product was fluid and was fractionally distilled under vacuum. The fraction boiling at 230-240 Grand 1 mm. of pressure consisted of phthalimidoisopropyl linoleate. Analysis of this compound gave a value of 3.03% nitrogen as against a calculated value for the compound of 3.00%.

EXAMPLE 5 Naphthalimidoethyl acetate EXAMPLE 6 Phthalimz'doz'sopropyl iso-valerate In the equipment as is described in Example 2, was heated at 190-225 C. for 4.5 hours a mixture of 1 mole of phthalic anhydride and 1.2 moles of 2-isobuty1-5-methy1 oxazoline. After reaction, the product was distilled under vacuum and the main fraction collected at 1'70-190 C. and 3 mm. pressure represented a yield of the isovalerate equal to 90% of theory. The distilled material crystallized on coolin to room temperature.

EXAMPLE 7 Phthalimidoisopropyl Zaurate This product which is a crystalline solid at room temperature was prepared in a 93 yield by heating 1 mole of phthalic anhydride and 1.1 moles of 2-undecyl-5-methyl oxazoline at 240 C. for 2.5 hours. The product distilled at 200-210 C. and. 1 mm. of pressure and had a nitrogencontent of 3.7% as against a calculated value of 3.62%.

EXAMPLE 8 Phthalimz'doisopropyl "linoleate One half mole of phthalic anhydride and 0.55 mole of the mixed oxazolines, derived from the mixed fatty acids of soybean oil of which the major component is linoleic acid, were agitated and heated at 200 C. for 3 hours under an atmosphere of nitrogen. The reaction mixture was then transferred to a modified Claisen distilling flask and was fractionally distilled under vacuum. The phthalimidopropyl ester of soybean oil fatty acids which was-collected at 2403-260? C. andl mm. of pressure was equal to a 72% yield.

EXAMPLES 9-23 hydride with standard caustic s'olution." Following is a tabulation of the reactants and the extent to which they reacted with the formation of the corresponding phthalim-ido or naphthalimido esters or thioesters.

Anhydride Azoline 3333: i

I Percept- Phthalio. 2-Undccyl-5-methyl oxazollne 97.5 Dichloroph do 91. 9 'I etrachlorophthalic; 54.4 l,8 Naphthalic; 69. 3 1 3 Nitrophthalic 'do. w 86.1 Dlchlorophthall Z-Methyl oxazoline 0 85.1 Dichlorophthah 2-Methyl-5-methyl thiazol1ne 67:0 Phthalic.. Q-p-Chlorophenyl oxazoline 86.5 Dichlorophthaliv do 76. 1 Naphfhalic rin 65. 2 Naphthalic Z-Methylthiazoline 82. 0 Phthalic 2-Phenyl-4,4,5-trimethyl oxazoline- 81.0 Phthalic 2-p-Nitrophenyl-5-ethyl oxazoline. 93.0 3 -Nitrophthalic "do 67.3 Sulfaphthalic Z-Heptadecyl-fi-methyl oxaz0line.- ca.

EXAM'PLE 24 Phtha limidoethyl thz'oacetate By the process of Example 2, one half mole each of phthalic anhydride and Z-methyl thiazoline were heated at C. for one hour. The acid number of the product was 39.2, corresponding to 91% of complete reaction to phthalimidoethyl thioacetate. The product when recrystallized from ethanol had a melting point of 113-114" C. and a sulfur-content of 12.96% by analysis.

It will be noted from the above examples that the naphthalic anhydrides react in the same way as the phthalic anhydrides and that the oxazolines and thiazolines also react alike. It will also be noted that the substituents represented by the R-characters do not take part in the reaction and do not interfere with the reaction between the anhydrides and the azolines.

The products of this invention have a wide variety of uses. Many of them have marked properties as regulants for plant growth. Others, especially those containing sulfur, are efiective as lube oil-additives. Still others, particularly those which contain long hydrocarbon substituents, or a plurality of shorter hydrocarbon groups, are useful as plasticizers for synthetic plastics.

I claim:

1. A process for the preparation of p-phthalimidoethyl esters and p naphthalimidoethyl esters of the general formula in which X represents an atom of an element from the class consisting of oxygen and sulfur; Z represents a divalent radical from the class consisting of phenylene and naphthylene radicals; the characters R R R and R represent members of the class consisting of hydrogen atoms anemia and alkyl, aryl, alkaryI, araik'yl', and cycIoalkyl groups and R represents a member of the class consisting of alkyl, aryl, aikaryl, aralkyl, and cycloalkyl groups and monounsaturated and diunsaturatedaliphatic hydrocarbon groups containin not more than 17 carbon atoms, which process comprises chemically reacting at a tem-- perature of 20 C; to 300 C. equimolar amounts'of (-1) a member of the class consisting of phthaiic and naphthalic anhydrides and (2 an azoline of the general formula cally reacting at a temperature from 50 C. to

250 C. equimolar amounts of-.phtha1ic anhydride and 2-heptadecadieny1-5-methy1oxazoline.

6. A process for the preparation of phtha1- imidoiso-propyl stearate which comprises chemically reacting at a temperature from 50 C. to 250 C. equimolar amounts of phthalic anhydride J and 2-heptadecy1-5-methyl oxazoline.

STANLEY P. ROWLAND.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,256,157 Watt Sept. 16, 1941 FOREIGN PATENTS Number Country Date 15113272 Switzerland Jan. 16, 1931 563,635 Great Britain Aug. 23,1944 

1. A PROCESS FOR THE PREPARATION OF B-PHTHALIMIDOETHYL ESTERS AND B - NAPHTHALIMIDOETHYL ESTERS OF THE GENERAL FORMULA 